Pair Of Straight Lines Question 138
Question: The circumcentre of the triangle formed by the lines $ xy+2x+2y+4=0 $ and $ x+y+2=0 $
[EAMCET 1994]
Options:
A) (0, 0)
B) (-2, - 2)
C) (-1, -1)
D) (-1, -2)
Show Answer
Answer:
Correct Answer: C
Solution:
The separate equations of the lines given by $ xy+2x+2y+4=0 $ are $ (x+2)(y+2)=0 $ or $ x+2=0 $ , $ y+2=0 $ .
Solving the equations of the sides of the triangle, we obtain the coordinates of the vertices as $ A(-2,0),\ B(0,-2) $ and $ C(-2,-2) $ .
Clearly, $ \Delta ABC $ is a right angled triangle with right angle at C.
Therefore the centre of the circum-circle is the midpoint of AB whose coordinates are (-1, -1).
BETA
